Stars

We all know what a star is. It is a massive, luminous ball of plasma that is held together by gravity. The sun, of course, is the nearest star to Earth and is the main source of energy for Earth. Not all stars are like our sun. They come in various sizes, colours, brightness and temperatures.

Stars are powered by a process known as nuclear fusion which requires a minimum temperature to occur, and only stars with a mass of at least 0.08 solar masses are able to sustain nuclear fusion. Stars below this threshold are known as brown dwarfs. They cannot fuse hydrogen (though some are capable of fusing deuterium).

Hydrostatic Equilibrium

A star's life is a constant struggle against gravity. Since stars are made of plasma and gas, they can be compressed by gravity with no rigidbody forces to stop it from imploding. Thus, there must exist some outward that acts against gravity to stabilise the star, if not, we would not be here today. In the case of stars, the outward pressure comes in the form of radiation pressure generated from nuclear fusion. We call this stable state of the star hydrostatic equilibrium. A star can only exist so long as it is in hydrostatic equilibrium. Unfortunately, the star cannot remain in this state forever but that's a story for another section.

Memes

Before, we begin, let us watch a video made by your seniors - Are all stars like our sun???